This program project proposal Virology and Genetics of Cancer focuses on the use of molecular genetic techniques to investigate the role of viral and cellular oncogenes in the pathogenesis and biology of human cancer. It also addresses the question of how specific oncogenes inserted in the appropriate retrovirus vectors may affect the differentiation program of stem cells. As a result of the previous studies on the expression of tumor associated antigens on gastrointestinal tumors and on the anti-tumor action of monoclonal antibodies directed against antigens expressed on human cells, we also propose new immunotherapeutic approaches to the treatment of human cancer.